Liquid crystal dimers containing Cholesteryl and Triazole-containing mesogenic units

Liquid crystalline dimers containing a cholesteryl benzoate unit: smectic phase, chiral nematic phase and blue phase

“…5. This peak corresponds to about half a molecular length, and according to the literature, 38 the intensity of this peak does not match that of the peak corresponding to the completely intercalated smectic phase. While the XRD curves in the literature 38 show that peaks corresponding to the full molecular length should appear at a smaller angle.…”

“…This peak corresponds to about half a molecular length, and according to the literature, 38 the intensity of this peak does not match that of the peak corresponding to the completely intercalated smectic phase. While the XRD curves in the literature 38 show that peaks corresponding to the full molecular length should appear at a smaller angle. Due to the lack of sensitivity of the instrument in the small angle area, the intensity of the background was too strong, so it was not possible to observe the peak corresponding to the full molecular length.…”

“…Arwa Al-shargabi et al synthesized a novel cholesterol-based non-symmetric liquid crystal dimer by linking two cholesterol molecules through triazole and alkyl spacers. 38 Homologues with an odd number of alkyl spacer groups show a chiral nematic phase, TGB phase, and chiral smectic C phase, and homologues with an even number of alkyl spacer groups show a chiral smectic A phase and chiral smectic C phase. The presence of three nitrogen atoms caused a strong polarization of the whole molecule, which resulted in dielectric anisotropy and a change in the phase transition temperature.…”

Enantioselective Synthesis of 3-Aryl-3-hydroxypropanoic Esters as Subunits for Chiral Liquid Crystals

“…Chirality, i.e., the geometric property of an object not being superimposable on its mirror image, is an important research topic in a wide range of scientific and technological areas, especially in soft materials due to their huge potential for applications in diverse fields. − Liquid crystals (LCs) are dynamic functional soft materials that share the anisotropic properties of the crystalline state and the fluidity of a liquid. The molecular shape, microsegregation of incompatible parts, and specific molecular interactions drive the process of self-assembly and self-organization toward the formation of various LC phases. , The introduction of chirality into LCs results in various chiral liquid crystalline phases such as the cholesteric, chiral smectic, twist grain boundary (TGB), and blue phases (BP), each with unique properties. , Emerging new technologies based on chiral LCs (e.g., smart windows, biosensors, 3D tunable lasers) highlight the need to design and engineer new chiral molecules that self-assemble in predictable ways to produce materials that have desirable properties. ,, Despite the variety of the known chiral LC structures, chirality is mainly introduced by the incorporation of a readily available cholesterol unit − or chiral precursors bearing a methyl group at the chiral center. ,, Both chiral subunits suffer from several limitations. The structural variations of cholesterol-based materials are limited due to their monofunctional structure which allows extension only via esterification of the 3-hydroxy group, and there are no readily available racemic modifications.…”

New azobenzene liquid crystal with dihydropyrazole heterocycle and photoisomerization studies

“…On the other hand, the introduction of heteroatoms with high polarization, such as S, O and N can affect the polarity and geometry of molecules, thus affecting the phase transition temperature, dipole moment, dielectric constant and even the type of liquid crystal phase [15]. Therefore, the liquid crystal with heterocyclic ring plays an important part in the design and synthesis of new functional materials and has become one of the research hotspots in recent years [16][17][18][19][20][21][22]. Among them, pyrazole heterocyclic ring has been widely used in material chemistry [23], biological and pharmaceutical industry [24][25][26][27] and others because of its high stability and strong dipole moment.…”